Effect of Outward Oxygen Protrusion on Surface Activated Bonding in LiTaO ₃

We study the tensile strength of the interfaces of amorphous lithium tantalate (LiTaO 3 ) and amorphous substrate materials, Al 2 O 3 and SiO 2 , to investigate the mechanism behind the surface activated bonding. We utilize universal neural network potential to simulate the formation and exfoliation of the interface between LiTaO 3 and a substrate in the atomistic scale. The simulated tensile strengths agree with the trends in the experimental values. We argue that the difference between the tensile strength of LiTaO 3 /Al 2 O 3 and that of LiTaO 3 /SiO 2 is caused by the difference in the surface structures of these substrate materials. The surface of amorphous SiO 2 contains more protruded oxygen atoms than that of the Al 2 O 3 surface. The protrusion prevents the formation of interface chemical bonds, resulting in a weak tensile strength in LiTaO 3 /SiO 2 .